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I rounded off a triple-square bolt while trying to undo it with a regular 6-point Torx bit. How can I undo it without resorting to purchasing a dedicated triple-square bit?

The bolt is done up with blue Loctite and is in a recessed area, so it isn't easy to wrap a pair of vice-grips around it.

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I have asked around and can't seem to find a shop that sells a three-squares bit, hence the question – Zaid May 12 '14 at 20:45
In the State they are easy to find at most auto parts stores. Not sure where to send you there, other than ordering online. – Move more comments link to top May 12 '14 at 21:57
Stupid question: Is a "three-squares" and a "triple square" the same head? If so, a large enough square head bit should foot the bill. If I'm looking at the right one, the triple square has twelve internal points. Even if you had to hammer it into the slot, I'm pretty sure this would give you enough bite to get the screw out. If not, is there enough room to get a pair of Vice-Grips on the outside? – Paulster2 May 12 '14 at 23:36
@Paulster2 : Access is tight as the bolt's in a recessed area, so vice-grips won't have enough purchase (plus it doesn't help that the bolt is done up with blue loctite). And yes, I think triple square refers to the same bolt. I ought to take a picture and post up when time permits. – Zaid May 13 '14 at 1:37
When I said "cut a slot", I was talking about using a Dremel tool (or some sort of grinder) to cut the slot. I would not use a chisel, which would get very ugly. And, yes, procuring the 12-point bit would be the best approach. – Paulster2 May 13 '14 at 10:23

2 Answers 2

I'm having the same problem right now. I tried a correctly-sized triple square .. but it still stripped .. (seat-belt retaining bolt on a VW) perhaps due to the thread-lock compound and the pressure involved.

After calling around, mechanics suggest:

  1. Using an angle grinder (very gradually) to grind off two sides (four sides if you're good) to get a spanner/wrench around the head of the bolt.
  2. Heat the bolt (then let it cool) before attempting to undo it with the spanner to break the lock-tite.

I'm having mixed success because of the recess, but maybe it'll help you.

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Heat it up to break the thread-lock compound. Tool selection isn't going to matter much if the thread-lock won't release. Probably the reason you stripped it in the first place? Anyway, after it's properly heated, you should be able to get it out with vise-grips, or by cutting a slot for a standard screwdriver. The issue you're facing is the lock-tite though - deal with that and then you have options.

I've also had some luck with stripped hex heads by simply hammering a flat-head screwdriver of the right size into the remaining corners, but keep in mind, everything like that you try will make the problem worse if it doesn't work.

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